Go Down

Topic: sensing mains power (Read 2 times) previous topic - next topic

yesyes


Quote
Does this look OK?

Looks fine, appart from the fact I would also have a resistor in line with the LED. The only thing limiting the current is te 470R and the 0.15uF cap, I am not sure if that will pass too much current.


How would you calculate the value for that resistor?
Chris

Location: Berkshire, UK
My Astro and DIY projects website: http://yesyes.info/

yesyes


you can use an AC 230V (or 110V) microrelay to send a DC signal to your arduino. Simple!


Not a bad idea. But I can't find one that is smaller than the LED circuit....
Chris

Location: Berkshire, UK
My Astro and DIY projects website: http://yesyes.info/

yesyes


Quote
A capacitor over led/optocoupler is no problem.

Except for the voltage rating it has to be.


The "flashing LED" circuit on the web page I linked to uses a 47uF 10V capacitor. Do you think the capacitor should be rated as high as the "mains dropper" capacitor?
Chris

Location: Berkshire, UK
My Astro and DIY projects website: http://yesyes.info/

Grumpy_Mike

No 10V is fine because the Zener and the LED means it dosn't get more than 10V across it.

Docedison

There are 2 better Idea's I can come up with one (the simplest is a relay connected to the mains, 230V relays are common and cheap, the second and better one is an LDR and a neon light. About 10 years ago I designed a radio remote controller for a center pivot irrigation controller and I Tried several times to use Led's for 220 Vac sensing. After literally blowing SEVERAL OF THEM off of The board I tried to use wall warts to save the board design, I bit the bullet and shrink tubed a NE2 to an LDR snd Never had a problem again and the LDR NE2 combination was about $0.10 cheaper after the part price had been burdened by the assembly time my girls spent putting them together. If adequately being shielded from light totally I could measure a low on a pin 2 or 3 times in succession, I knew that the power was on at the point being monitored, didn't need filters, caps or special software just a completely light shielded LDR and 2 or 3 low measurements were more than enough... that and a .1 uF cap for the occasional transient. I didn't write the code for that job but it was written to my specifications and the "engineer" doing the code had no problems measuring the pin. Just a thought...

Doc
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

Go Up